The background description provided herein is for the purpose of generally presenting the context of the present invention. The subject matter discussed in the background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art. The subject matter in the background of the invention section merely represents different approaches, which in and of themselves may also be inventions.
A syringe is the most frequently used medical instrument clinically. The most common syringe used at present is a disposable syringe made of plastic. Although, the disposable syringe has effectively controlled the problems of cross infection, along with the progress of technologies, a one-way protection concept falls behind. A syringe needle polluted by patient's blood in a use process may harm a user, and the discarded syringes also may accidentally harm those people in a subsequent storage, transportation and destroying process. Besides, the existing disposable syringe has the defects of reuse if kept intactly, exposure of the syringe needle after injection due to no safety apparatus, etc. Thus, lawbreakers can reuse the used discarded disposable syringes without disinfection, leading to great probability in virus propagation and cross infection. Therefore, a multi-way protection concept occurs along with the trend. The safety syringe is a medical instrument in the multi-way protection concept, and it not only protects a patient from cross infection, but also protects medical staff using it and personnel who may contact it subsequently from the harm of the syringe needle.
Currently, there are many products and patents of retractable safety syringes available, for example, CN 100443130C, CN 103330976B, U.S. Pat. No. 9,155,845, U.S. Pat. No. 8,562,561, JP2008-525059, and JP2012-086057. Some of them have complicated structures, especially, some of them have more than seven parts, cannot be produced in batch and are high in production cost; some of them cannot use a standard injection needle or cannot exchange the needle; some of them use an O-shaped ring to solve an airtightness problem of a cylinder, but the O-shaped ring is small in size and is difficult in implementation of mechanical assembly; some of them cannot inject for many times, the safety apparatus is activated when a plunger is pushed to the bottom and most of them are not equipped with a function of selectively activating the safety mechanism.
Article 3.1 of International Standards ISO7886-4 Sterile hypodermic syringes for single use-Part 4: Syringues with reuse prevention feature puts forth requirements of selectively activating the safety mechanism by a user himself/herself.
Chinese Patent Application No. CN200820200380.3 (i.e., Publication No. CN201290969Y) discloses a self-destruction safety syringe, it comprises a cylinder, a push rod, a piston, a connector and a needle holder, where a clamping position is disposed between the connector and the cylinder, an elastic clamping slot is disposed in a connector inner hole and the top end of the push rod is provided with an auxiliary rotating device capable of rotating the connector along with the push rod. A self-destruction process of the self-destruction safety syringe is as follows: after injection, the pull rod pulls needle holder back into the cylinder by slightly pressing the push rod and matching clamping device, then the push rod is broken along a breaking recess in the push rod and is placed back into a recycling box. The self-destruction safety syringe can be self-destroyed after use, but the self-destruction can be guaranteed as long as an operator breaks the push rod, it is troublesome to operate, and has demand on a breaking force applied to the push rod, and the push rod cannot be broken in case of not enough force.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.